Analysis of the Reflection Coefficient of Rayleigh Waves From Surface-Breaking Cracks

2000 ◽  
Author(s):  
Waled Hassan ◽  
William Veronesi
Keyword(s):  
Reflection Coefficient ◽  
Rayleigh Wave ◽  
Acoustic Waves ◽  
Near Field ◽  
Crack Depth ◽  
Wave Length ◽  
Surface Acoustic Waves ◽  
Finite Size ◽  
High Crack ◽  
Limiting Value

Abstract The interaction of surface acoustic waves with finite-size, surface-breaking, semi-circular cracks is studied theoretically, numerically, and experimentally. We focus on the behavior of the reflection coefficient of the Rayleigh wave from such cracks in both the far and near fields of the crack. It is shown that, in the near field, the reflection coefficient from such cracks is higher than the reflection coefficient measured in the far field. This is mainly due to the diverging nature of the Rayleigh wave reflected from the crack. In the high crack depth to wave length ratio, the finite element and experimental results approach the limiting value of the reflection coefficient from a 90-degree corner.

Design Development of Acoustic Waves Based Sensitive Sensors for Escherichia coli O157:H7 Detection

2014 ◽  
Vol 925 ◽  
pp. 590-594 ◽  
Author(s):  
Seng Teik Ten ◽  
Uda Hashim ◽  
Ahmad Sudin ◽  
Wei Wen Liu ◽  
Kai Loong Foo ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Acoustic Waves ◽  
Low Cost ◽  
Wave Length ◽  
Surface Acoustic Waves ◽  
High Volume ◽  
Acoustic Energy ◽  
Label Free ◽  
Design Development ◽  
Fecal Matter

Food contamination has become critical issue and is being worse due to the insensitive detection devices. One of the dangerous food contaminations is by Escherichia coli (E.coli) O157:H7, one of the harmful bacterial pathogens which is distributed in soil, marine and estuarine waters, the intestinal tract of animals, or water contaminated with fecal matter. A small amount of E.coli with the dose fewer than 100 organisms in food products or water is enough to cause serious gastrointestinal illness to human. Hence, the ultra-high sensitive, label free biosensors have been designed in this research for the low concentration E.coli detection. Surface acoustic waves (SAW) devices have been initially developed and used for the high-volume low-cost TV component. Due to the ultra-sensitivity to the surface perturbation, SAW based devices have been modified to be sensors. Initially, SAW sensors were developed for gas detections and have been moving towards biological detections recently. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid. However, the main SHSAW design components are the operating frequency and wave length. These are strictly depended on the inter digital transducers (IDTs) design. Therefore, this paper is presenting the IDTs design concept and pattern development by using computer aid design (CAD) software.

scholarly journals The influence of adsorbed atoms concentration on the temperature coefficient of resonant frequency of the quasi-Rayleigh wave

2021 ◽  
Vol 24 (1) ◽  
pp. 13401
Author(s):  
M.Ya. Seneta ◽  
R.M. Peleshchak ◽  
A.I. Nesterivskyi ◽  
N.I. Lazurchak ◽  
S.K. Guba
Keyword(s):  
Resonant Frequency ◽  
Rayleigh Wave ◽  
Temperature Coefficient ◽  
Acoustic Waves ◽  
Surface Acoustic Waves ◽  
Acoustic Mode ◽  
New Class ◽  
Zinc Blende ◽  
Adsorbed Atoms ◽  
Zinc Blende Structure

Within the model of self-consistent connection of quasi-Rayleigh wave with adsorbed atoms, a method of constructing a new class of radiometric sensors of the temperature and concentration of adsorbed atoms on the surface acoustic waves is proposed. Based on the developed theory of the dispersion and acoustic mode width of a quasi-Rayleigh wave on the adsorbed surface of monocrystals with a Zinc blende structure, the temperature coefficient of the resonant frequency of the surface acoustic wave is calculated depending on the temperature and on the concentration of adsorbed atoms.

Characterization of RF Sputtered ZnO Piezoelectric Films Using Transmission Electron Microscope

1975 ◽  
Vol 33 ◽  
pp. 86-87
Author(s):  
Kemining W. Yeh ◽  
Richard S. Muller ◽  
Wei-Kuo Wu ◽  
Jack Washburn
Keyword(s):  
Integrated Circuit ◽  
Acoustic Waves ◽  
New Technology ◽  
Surface Acoustic Waves ◽  
Electromechanical Properties ◽  
Leading Role ◽  
Saw Devices ◽  
Transmission Electron ◽  
High Degree

Considerable and continuing interest has been shown in the thin film transducer fabrication for surface acoustic waves (SAW) in the past few years. Due to the high degree of miniaturization, compatibility with silicon integrated circuit technology, simplicity and ease of design, this new technology has played an important role in the design of new devices for communications and signal processing. Among the commonly used piezoelectric thin films, ZnO generally yields superior electromechanical properties and is expected to play a leading role in the development of SAW devices.

Attenuation of surface acoustic waves by quantum dots

1998 ◽  
Vol 77 (5) ◽  
pp. 1195-1202
Author(s):  
Andreas Knabchen Yehoshua, B. Levinson, Ora
Keyword(s):  
Quantum Dots ◽  
Acoustic Waves ◽  
Surface Acoustic Waves
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